1. Field of the Invention
The present invention is related to a ratchet diving mask strap of which the tightness adjustment is more convenient, practicable and comfortable even under water.
2. Description of the Prior Art
As one of the three diving necessities (diving mask, snorkel and fins), the diving mask is prerequisite equipment for the divers who require the mask to fit faces in addition to the mask lens being very transparent. Such demand for safety depends on the combination of mask skirt and mask strap of diving mask. A clearance between the mask skirt and diver's face or a poor tightness of mask strap will result in water leakage and permeation to unfavorably affect the function of a diving mask as a whole. Of course, the divers know that the deeper they dive, the more obvious the effect on the water leakage and permeation of diving mask, therefore, the suitable tightness adjustment of mask strap is very important.
The major structure of diving mask in general comprises a frame(11), a skirt(12) and a strap(13) as shown in FIG. 1, and the strap(13) of conventional diving mask is integrally molded into a strap made of elastic material such as rubber, silicone, wherein the two ends of said strap(13) are respectively folded reversely to connect the two sides of frame(11), and the tightness adjustment thereof is roughly done by means of pulling the reversely folded strap in the position of connection to an extent of neither too tight nor too loose so far as the elastic force that it is said strap(13) is concerned. However, adjusting too loose will lead to water permeation and leakage under water, but adjusting too tight will considerably pressurize the diver's head and face, his head will feel uncomfortable so he cannot dive for a long time. In addition, the said adjustment has to be done before diving but cannot be done any more under water. It is necessary to improve the limitation on use and the undesirable safety.
In view of the foregoing drawbacks of the conventional diving mask strap, the present inventor offers an adjustable diving mask strap which adopts the two-piece opposite displacement tightening method--to turn the adjusting knob to tighten the two sides of strap to an extent of suitable tightness to combine the effect of both the elastic force tightening and the knob adjusting, namely, suitable tightness, comfortable wearing and considerable practice, and the mask strap tightness can be adjusted under water from time to time as required.